Apparatus for building a tobacco stream

ABSTRACT

A distributor for comminuted tobacco wherein a first conveyor, such as a carded drum, an endless apron or a pneumatic conveyor, supplies tobacco at a variable rate into the path of orbital movement of bristles on a rapidly rotating accelerating device. The bristles propel the particles of tobacco onto a narrow foraminous transporting belt which travels in a horizontal channel and accumulates a dense tobacco stream which is transported past a trimming device and into the wrapping mechanism of a cigarette rod making machine. The accelerating device is driven by a separate motor so that the peripheral speed of its bristles exceeds the speed of tobacco travel on the first conveyor. The stream is attracted to the transporting conveyor by suction, and the accelerating device is placed sufficiently close to the channel to insure that, during impact against the transporting conveyor or against the layer of tobacco thereon, the kinetic energy of all or nearly all tobacco particles is substantially identical. The accelerating device can be placed below, between or above the first conveyor and transporting conveyor and may form part of a winnowing assembly.

BACKGROUND OF THE INVENTION

The present invention relates to improvements in apparatus for buildinga tobacco stream. More particularly, the invention relates toimprovements in apparatus which can be utilized as distributors inmachines for the making of a continuous wrapped tobacco filler rod whichis ready to be subdivided into plain cigarettes, cigars or cigarillos ofunit length or multiple unit length. One of the presently preferred usesof the improved stream building apparatus is as a distributor for acigarette rod making machine.

As a rule, the distributor of a cigarette rod making machine comprises amagazine for a supply of tobacco shreds or for a mixture of tobaccoshreds and ribs, and an apron which withdraws a relatively wide carpetof tobacco from the magazine and showers it into a channel having abottom wall formed by the upper stretch of an endless conveyor beltwhich transports the growing tobacco stream toward the next processingstation, such as a station accommodating a trimming or equalizing devicewhich removes the surplus of tobacco and thereby converts the streaminto a filler rod. The moving parts of the distributor are normallydriven at a variable speed in synchronism with other components of thecigarette rod making machine so that the rate at which the distributordelivers a continuous tobacco stream corresponds to the rate at whichthe machine can process tobacco to form a continuous wrapped filler rod.

In many instances, the tobacco which forms a relatively wide carpet.[.of.]. .Iadd.or .Iaddend.sliver is caused to leave the discharge endof the apron by gravity and to descend into the channel wherein it formsa growing tobacco stream. This practice is normally resorted to in themanufacture of cigarettes, cigars or cigarillos as well as analogousrod-shaped smokers' products. It is also known to draw the tobaccostream into the channel by suction whereby the stream transporting beltcan be located at a level above or below the apron. It is also customaryto place a suction chamber adjacent to the stream transporting belt soas to insure that the particles of tobacco are attracted to the belt andcannot slip during transport toward the next processing station.

It is well known that the trimming operation is facilitated if thetobacco stream which advances into the range of the trimming deviceexhibits a uniform density throughout its entire cross section. It isalso known that the tobacco stream should preferably have a constant ornearly constant height so that the trimming device removes a nearlyuniform layer of surplus tobacco. This cannot be readily achieved inpresently known distributors which almost invariably produce a tobaccostream with pronounced hills and valleys so that the layer of tobaccowhich is removed by the trimming device includes portions of differentheight or depth. The formation of hills and valleys is due to the factthat, when the particles of tobacco descend by gravity or are pulled bysuction against the adjacent surface of the continuously travellingstream transporting belt, even minor variations in uniformity of tobaccodelivery can cause certain unevennesses in the exposed surface of thegrowing tobacco stream. Such unevennesses become more pronounced as thetobacco stream continues to grow because the freshly admitted particlesare likely to accumulate at the front sides or leading slopes of hillswhereby the height of hills increases and the difference between theheight of the tobacco stream below the valleys and below the hillsbecomes more pronounced. Such building of tobacco streams is undesirablebecause even the shallowest portion of the stream must at least slightlyexceed the height or thickness of the filler so that the trimming devicemust remove substantial quantities of tobacco with attendant comminutionof tobacco shreds and the formation of tobacco dust. Furthermore, theaction of suction upon the particles which form the tobacco stream alsocontributes to differences in density of the tobacco stream. The effectof suction is a function of the height of the adjacent portion of thetobacco stream and of the position of tobacco particles relative to eachother. Thus, the particles which are immediately adjacent to thetransporting stretch of the belt are properly attracted by the suctionchamber whereby the innermost portion of the growing tobacco streamundergoes a rather pronounced densifying or compacting action. However,as the distance between the particles of a growing stream and thesuction chamber increases, the effect of suction upon the outermostportion of the tobacco stream decreases so that the outermost portion ofthe growing stream exhibits a much less pronounced density than theportion which is immediately adjacent to the transporting belt.Consequently, those portions of a tobacco stream which form the hillsare subjected to a much less pronounced densifying action than theportions below the valleys which are closer to the belt. Moreover, thesuction cannot be increased at will because this would further promotethe difference between the density of a tobacco layer which isimmediately adjacent to the belt and the tobacco layer or layers whichare more distant from the belt. Also, if the density of the tobaccolayer which is immediately adjacent to the belt is increased beyond acertain limit, the porosity of such layer decreases to such an extentthat the currents of air cannot attract the particles in the outerportion of the stream, i.e., the outermost particles are likely to moverelative to the belt and thus remain in the stream building zone.

SUMMARY OF THE INVENTION

An object of the invention is to provide a novel and improved apparatuswhich can build a tobacco stream wherein all portions exhibit the samedensity or substantially identical density.

Another object of the invention is to provide a novel and improveddistributor for use in machines for the production of wrapped tobaccofiller rods which can be subdivided to yield plain cigarettes, cigars orcigarillos of unit length of multiple unit length.

A further object of the invention is to provide a stream buildingapparatus with novel and improved means for transferring tobacco betweena first conveyor which advances tobacco in the form of a carpet or layerand a second conveyor which transports tobacco in the form of a narrowstream.

An additional object of the invention is to provide a distributor foruse in a cigarette rod making or analogous machine with novel andimproved means for regulating the density of the growing tobacco stream.

An additional object of the invention is to provide a distributor withnovel and improved means for compacting the particles of a growingtobacco stream without any or with minimal reliance upon suction.

Another object of the invention is to provide a distributor which can beused as a substitute for presently known distributors in existingmachines for the production of wrapped tobacco filler rods.

The invention is embodied in a machine for the making of wrapped tobaccofiller rods, and more particularly in an apparatus for building in sucha machine a continuous tobacco stream, for example, a stream of shreddedtobacco which can be converted into the filler of a wrapped cigaretterod.

The stream building apparatus comprises a magazine, hopper or ananalogous source of comminuted tobacco, a tobacco feeding unit which isarranged to receive or draw tobacco from the source and includes a firstconveyor operable at a plurality of speeds (preferably in synchronismwith other moving parts of the filler rod making machine) to transportthe withdrawn tobacco along a first portion of an elongated path whichextends through the tobacco filler rod making machine, a preferablynarrow belt-like tobacco stream transporting second conveyor which isadjacent to a second portion of the path, an accelerating device whichis disposed between the conveyors and is operative to mechanicallyaccelerate comminuted tobacco for transfer into the second portion ofthe path wherein the accelerated tobacco forms a growing stream which istransported by the second conveyor, and means for operating theaccelerating device independently of the second and/or first conveyor.

The accelerating device may include a rotary conveyor, for example, adrum provided with an elastic or yieldable (deformable) peripheralportion including or consisting of substantially radially extendingbristles or pins. The operating means for the acceleraing device maycomprise a variable-speed motor or transmission which drives theaccelerating device at a speed exceeding the speed of comminuted tobaccoon the first conveyor. The accelerating action of the bristles ispreferably selected in such a way that the density of the stream on thesecond conveyor considerably exceeds half the density of the wrappedfiller rod.

The first conveyor can discharge comminuted tobacco by gravity; it maycooperate with a picker roller; or it may deliver comminuted tobaccointo a pneumatic conveyor for transport into the range of theaccelerating device. The latter may be mounted at a level between thefirst and second conveyors, at a level above the second conveyor, at alevel above the first conveyor, at a level below the second conveyor, orat a level above both conveyors.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved tobacco stream building apparatus itself, however, both as toits construction and its mode of operation, together with additionalfeatures and advantages thereof, will be best understood upon perusal ofthe following detailed description of certain specific embodiments withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 (composed of FIGS. 1a and 1b) is a schematic elevational view ofa machine for the making of a wrapped tobacco filler rod which includesa tobacco stream building distributor constucted and assembled inaccordance with a first embodiment of the invention;

FIG. 2 is an enlarged fragmentary transverse vertical sectional view ofthe distributor as seen in the direction of arrows from the line II--IIof FIG. 1a;

FIG. 3 (composed of FIGS. 3a and 3b) is a schematic elevational view ofanother machine for the making of a wrapped tobacco filler rod whichembodies a different tobacco stream building distributor;

FIG. 4 (composed of FIGS. 4a and 4b) is an enlarged transverse verticalsectional view as seen in the direction of arrows from the line IV--IVof FIG. 3a;

FIG. 5 is a fragmentary transverse vertical sectional view of adistributor which constitutes a first modification of the distributorshown in FIGS. 4a and 4b;

FIG. 6 is a fragmentary transverse vertical sectional view of adistributor which constitutes a second modification of the distributorshown in FIGS. 4a and 4b; and

FIG. 7 is a fragmentary transverse vertical sectional view of a furthertobacco stream building distributor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIGS. 1a and 1b, there is shown a cigarette rodmaking machine which comprises an overhead distributor 1 including anarrow elongated channel 3 (see also FIG. 2) wherein the component partsof the distributor build a narrow tobacco stream 2. The tobacco streambuilding zone is shown at A. The bottom wall of the channel 3 is formedby the upper stretch of an elongated tobacco stream advancing ortransporting conveyor 4 which is an endless foraminous bell trained overa number of rollers shown in FIG. 1a. A suction chamber 6 is provided ata level below the upper stretch of the stream transporting conveyor 4 toattract the particles of the tobacco stream 2 so that successiveincrements of the growing stream are compelled to advance in and beyondthe building zone A. The top wall of the suction chamber 6 is providedwith suction ports 6a (see FIG. 2). Since the material of the streamtransporting conveyor 4 is foraminous, the chamber 6 can draw smallcurrents of air therethrough.

Successive increments of the fully grown tobacco stream 2 advance intothe range of one or more cutters forming part of a trimming orequalizing device 7 which is adjacent to the upper stretch of the streamtransporting belt 4 downwstream of the zone A and which serves to removefrom the tobacco stream the surplus of comminuted tobacco so that thestream is converted into a rod-like filler which thereupon enters awrapping mechanism. The wrapping mechanism comprises a so-calledgarniture belt 13 having an upper stretch which travels below a drapingdevice 14, a paster 16, a heated sealer 17 and thereupon returns towardthe discharge end of the conveyor 4. The filler which is obtained upontrimming of the tobacco stream 2 is transferred onto the upper stretchof the belt 13 with the assistance from an endless steel belt 8 whichcauses successive increments of the filler to move onto and to advancewith an elongated web 9 of cigarette paper. The web 9 is stored in theform of a roll 9a and passes through a normally idle splicing device 10.A fresh roll 11 of cigarette paper is held in a position or readiness atthe splicing station so that its leader can be attached to the expiringweb 9 when the supply of web on the roll 9a has been depleted to apredetermined minimum value.

The draping device 14 of the wrapping mechanism is provided with meansfor converting the web 9 into a substantially U-shaped body whichsurrounds three sides of the filler and for thereupon folding onemarginal portion of such U-shaped body over the filler whereby only onemarginal portion extends from the partially wrapped filler to move alongthe paster 16 which coats it with a film of adhesive. The wrappingmechanism further comprises means for folding the adhesive-coatedmarginal portion of the web 9 over the other marginal portion to form aseam which is caused to set during travel along the sealer 17 so thatthe filler and the web 9 are converted into a continuous wrapped fillerrod or cigarette rod 18. The reference character 12 denotes in FIG. 1aan imprinting mechanism which is adjacent to the path of travel of theweb 9 from the splicing device 10 toward the upper stretch of the belt13 and provides longitudinally spaced portions of the web with printedmatter.

The wrapped filler rod 18 thereupon enters a conventional cutoff 19(shown in FIG. 1b) which subdivides the rod into discrete plaincigarettes of unit length. Such cigarettes form a single file and travelbelow a rapidly rotating accelerating cam 21 which propels successiveplain cigarettes into successive flutes of a rotating transfer conveyor22 here shown as a drum which transports plain cigarettes sidewaystoward a tray filling apparatus, to a packing machine or to a filtercigarette making machine. The cigarettes in the flutes of the transferconveyor 22 can form one or more rows. FIG. 1a further shows a mainprime mover 20 which is preferably a variable-speed electric motorserving to drive the majority of moving parts of the cigarette makingmachine. Such moving parts include the stream transporting conveyor 4,the belt 13 and the cutoff 19.

The wrapping mechanism shown in FIG. 1a further serves to densify orcompact the rod-like filler so that the contents of the wrapper of therod 18 are compacted to a predetermined extent.

FIG. 2 is a sectional view of the distributor 1 which includes thechannel 3 with the stream transporting conveyor 4. The distributor 1further comprises a tobacco feeding unit including a conveyor 23 hereshown as an endless apron which is trained over several rollers 24 (onlyone shown) and transports a relatively wide carpet or layer 23a ofcomminuted tobacco along a first portion of an elongated path. A secondportion of this path is adjacent to the upper stretch of the streamtransporting conveyor 4. The discharge end of the upper stretch of theapron 23 is located at a level above the channel 3, and the tobaccowhich is being discharged by this apron impinges upon an arcuate baffle33 to descend into a funnel 34 which is defined in part by the baffle 33and in part by the bristles 28 of a rotary accelerating device orconveyor 29. In accordance with a feature of the invention, theaccelerating device 29 is operated (rotated) independently of the apron23 by a discrete motor 32 through the intermediary of a belt or chaintransmission 31. The speed of the apron 23 varies in synchronism withthe speed of other moving parts of the cigarette rod making machine,i.e., the apron can be driven by the prime mover 20 shown in FIG. 1a. Asa rule, the machine of FIGS. 1a and 1b is driven at two differentspeeds, namely, at a lower speed immediately after starting andthereupon at a higher or normal operating speed at which the machine ofFIGS. 1a and 1b can turn out up to and in excess of 70 plain cigarettesper second.

Referring again to FIG. 2, the channel 3 is provided with side walls 26,27 flanking the particles of tobacco which are being propelleddownwardly by the bristles 28 of the rotating accelerating device 29.The upper portions of the internal surfaces of side walls 26, 27 divergeupwardly and outwardly toward the underside of the accelerating device29. The axial length of the accelerating device 29 preferably equals orapproximates the width of the apron 23 and corresponds to the length ofthe tobacco stream growing zone A shown in FIG. 1a. The speed of thebelt transmission 31 is selected in such a way that the peripheral speedof the accelerating device 29 exceeds the speed of lengthwise movementof the tobacco layer 23a on the apron 23. The tips of bristles 28preferably touch or come very close to the adjacent surface of thebaffle 33 so as to make sure that each and every particle of tobaccowhich enters the funnel 34 is accelerated and propelled in a directiontoward the space between the side walls 26 and 27 of the channel 3. FIG.2 further shows a second baffle 36 which is located below theacceleraing device 29 and has a concave side facing the adjacent lowerend portion of the baffle 33 to define therewith a passage wherein theaccelerated particles of comminuted tobacco travel toward the upperstretch of the stream transporting conveyor 4.

It will be noted that the accelerating device 29 is disposed at a levelbetween the apron 23 and conveyor 4 and that the apron 23 cooperateswith the baffle 33 to partially fill the funnel 34 with comminutedtobacco which descends into the funnel by gravity. The direction oftravel of tobacco on the apron 23 is normal to the direction of travelof tobacco on the conveyor 4.

The operation of the cigarette rod making machine of FIGS. 1a and 1b isas follows:

The upper stretch of the apron 23 shown in FIG. 2 receives a continuoussupply of comminuted tobacco which forms thereon the layer or carpet 23aand is advanced toward and beyond the illustrated roller 24. Theparticles of comminuted tobacco which advance beyond the discharge endof the apron 23 descend by gravity to enter the funnel 34 and to thusmove into the range of rapidly orbiting bristles 28 of the acceleratingdevice 29. Since the bristles 28 actually touch or come close to theadjacent surface of the baffle 33, all particles of tobacco which enterthe funnel 34 are accelerated at the same rate and are propelled intothe passage between the baffles 33 and 36 to thereupon enter the channel3 and to come to rest on the upper stretch of the continuously movingstream transporting conveyor 4. The particles which descend onto theconveyor 4 form the stream 2 which grows during travel along the zone Aand thereupon advances past the trimming device 7 of FIG. 1a. The energyof tobacco particles which are propelled by the bristles 28 greatlyexceeds the energy of tobacco particles which enter the funnel 34. Thisis attributed to the fact that the accelerating device 29 is driven at aspeed which exceeds the speed of the apron 23. The purpose of thesuction chamber 6 is to insure that the particles of tobacco which formthe stream 2 are attracted to the upper side of the conveyor 4 andtravel therewith in a direction toward the trimming station. The purposeof the baffles 33 and 36 is to confine the mass of accelerated tobaccoparticles which are being transferred from the funnel 34 into the spacebetween the side walls 26 and 27.

The accelerating action of the device 29 is preferably such that theparticles of tobacco which come to rest on the upper stretch of thetransporting conveyor 4 form a dense stream 2, namely, a stream whosedensity preferably greatly exceeds half the density of the filler in thewrapped rod 18 shown in FIG. 1a. For example, the density of the stream2 on the transporting conveyor 4 may approximate 75 percent of thedensity of the filler in the rod 18. Such compacting of tobaccoparticles which form the stream 2 is attributed to the fact that theparticles which are accelerated by the bristles 28 of the device 29 notonly descend on top of each other but, owing to their high kineticenergy, actually fill the interstices or gaps between the adjoiningparticles of tobacco (mainly tobacco shreds).

Such filling of interstices insures that the density of the stream 2greatly exceeds the density of a stream which would be formed if theparticles leaving the upper stretch of the apron 23 were allowed todescend onto the conveyor 4 merely under the action of gravity.

It was found that the compacting action of the accelerating device 29 issufficiently pronounced to insure that the expansion of the stream 2 inthe channel 3 is negligible or minimal if the suction in the chamber 6is terminated, i.e., if the ports 6a cease to draw currents of airacross the tobacco stream in the channel 3. In other words, theinfluence of suction chamber 6 upon the density of the tobacco stream 2on the upper stretch of the transporting conveyor 4 is extremely small,especially if compared with the compacting action of the acceleratingdevice 29.

The accelerating device 29 is preferably mounted close to the streamtransporting conveyor 4 to thus insure that the speed of particles ofcomminuted tobacco does not decrease materially during travel from theregion of contact with the bristles 28 onto the upper stretch of theconveyor 4 or onto the tobacco particles on this stretch. This insuresthat, during impact against the conveyor 4 or against tobacco particleson this conveyor, the kinetc energy of all accelerated tobacco particlesis at least substantially identical. Consequently, by properly selectingthe speed of the accelerating device 29, one can accurately determine inadvance the density of all portions of the tobacco stream 2 in thechannel 3 to thus insure that the particles are densely packed, notbecause of the action of suction chamber 6, but rather as a directresult of acceleration of tobacco particles by the orbiting bristles 28.Thus, the density of the topmost layer of tobacco particles which formthe stream 2 is identical with or closely approximates the density ofthat layer which is immediately adjacent to the upper stretch of thetransporting conveyor 4. The exact density depends on the selected speedof the accelerating device 29 or an analogous accelerating device.

If the density of the stream 2 substantially exceeds half the density ofthe filler in the rod 18, the friction between the internal surface ofthe channel 3 and the tobacco stream 2 is likely to reach a value atwhich some particles of the stream might be caused to move relative tothe transporting conveyor 4 or vice versa. The function of the suctionchamber 6 is to prevent or at least reduce the likelihood of movement ofthe upper stretch of the transporting conveyor 4 relative to thoseparticles of tobacco in the stream 2 which contact the internal surfacesof the channel 3.

FIGS. 3a and 3b illustrate a modified cigarette rod making machinewherein all such parts which are identical with or clearly analogous tothe corresponding parts of the machine shown in FIGS. 1a and 1b aredenoted by similar reference characters plus 100. The main differencebetween the machines of FIGS. 1a-1b and 3a-3b is that the tobacco streambuilding distributor 101 of FIG. 3a (shown in greater detail in FIGS. 4aand 4b) is designed to transport shredded tobacco, or a mixture oftobacco shreds and ribs or stem, upwardly and to thereupon deflect theshreds so that they descend onto the upper stretch of the streamtransporting conveyor 104.

Referring to FIGS. 4a and 4b, the distributor 101 comprises a tobaccofeeding unit having a conveyor 141 which corresponds to the apron 23 ofFIG. 2 and is shown in the form of a carded drum serving to draw amixture of randomly distributed tobacco shreds and ribs from a source150. The carded drum 141 cooperated with a drum-shaped refuser 142 ofthe feeding unit which removes from the carding of the drum 141 thesurplus of tobacco whereby the thus equalized sliver or layer of tobaccoshreds and ribs advances beyond the nip of the drums 141, 142 andtravels below a mechanical retainer 143 and into the range of a rapidlyrotating picker roller 144. This roller also forms part of the feedingunit and serves as a means for mechanically expelling successiveincrements of the sliver from the carding of the drum 141. The retainer143 may resemble a comb having a number of parallel prongs extending ata predetermined distance from the periphery of the continuously rotatingdrum 141. The speed of the drum 141 varies as a function of changes inthe operating speed of the cigarette rod making machine shown in FIGS.3a and 3b. The drum 141 can be driven by the prime mover 120 of FIG. 3a.

The particles of tobacco which are removed from the carding of the drum141 by the picker roller 144 are fed into the lower end portion of anupright pneumatic conveyor 146 here shown as a duct having orifices 149which enable its lower end portion to communicate with two discreteplenum chambers 147 and 148. The plenum chambers 147 and 148 arerespectively located at a level above and below the picker roller 144and are connected to each other by an air-supplying pressure pipe 161connected to the outlet of a source of compressed air here shown as ablower 159.

As shown in FIG. 4a, the upper end of the duct 146 is closed by a wall151 of the housing of the distributor 101 and by the adjacent bristles128 of the accelerating device 129. The wall 151 of the distributorhousing defines with the accelerating device 129 a first funnel 152 fromwhich the air is being withdrawn into a suction chamber 156 by way ofseveral downwardly inclined suction ports 154. The suction chamber 156is connected with the intake of the blower 159 by way of a suction pipe157 containing an air filter 158. The suction ports 154 are provided ina wall 153 of the duct 146.

The housing of the distributor 101 further defines a separator chamber162 located at a level above the accelerating device 129 and containingan adjustable baffle 164 whose inclination can be changed by anadjusting screw 163 mounted in the wall 151. The separator chamber 162further contains a receptacle 166 for heavier tobacco particles (mainlylarger fragments of ribs and/or stem) and a feed screw 167 which can beoperated continuously or intermittently to evacuate the contents of thereceptacle 166. The lower portion of the separator chamber 162accommodates a substantially semicylindrical guide 168 around which thelighter tobacco particles (mainly smaller fragments of ribs and shreds)travel on their way into a second funnel 171. This second funnel isdefined by the bristles 128 and a further wall 169 of the distributor101. The wall 169 is provided with an air-admitting opening 172containing an adjustable regulating valve 173. The wall 169 forms partof the channel 103 which contains the suction chamber 106 and receivesthe upper stretch of the foraminous conveyor 104 serving to support andtransport the growing and fully grown tobacco stream 102 during traveltoward the wrapping mechanism shown in FIG. 3a.

The purpose of the adjustable baffle 164 is to control the direction oftravel of heavier tobacco particles so as to make sure that suchparticles enter the receptacle 166. The regulating valve 173 controlsthe rate of admission of air which is being drawn across the tobaccostream 102 and through the openings of the transporting conveyor 104 toenter the suction chamber 106.

It will be noted that the accelerating device 129 is located at a levelabove the drum 141 and transporting conveyor 104 but below the separatorchamber 162, and that the duct 146 is located between the drum 141 andthe accelerating device 129.

The operation of the cigarette rod making machine including thestructure shown in FIGS. 3a, 3b, 4a and 4b is as follows:

The carded drum 141 of the feeding unit draws from the source 150 acontinuous layer of a mixture of tobacco shreds and ribs and advancesthe layer toward the lowermost portion of the refuser 142. The cardingof the refuser 142 returns the surplus to the source 150 and allows anequalized layer of the mixture to advance below the mechanical retainer143 and into the range of the rapidly rotating picker roller 144. Theparicles of tobacco thereupon enter the lower end portion of the duct146 and are entrained upwardly by the currents of air which are admittedby way of orifices 149 from the plenum chambers 147 and 148. It isassumed that the motor of the blower 159 is driven so that this blowersupplies into the pipe 161 a continuous stream of compressed air anddraws a continuous stream of air from the pipe 157 by way of the airfilter 158. The air which entrains the particles of tobacco in the duct146 is withdrawn through the suction ports 154 to enter the suction pipe157 and to be returned to the intake of the blower 159. It will be notedthat the inclination of ports 154 is sufficient to insure that theinertia of ascending particles of tobacco causes such particles to enterthe funnel 152. The bristles 128 of the accelerating device 129 touchthe adjacent protuberance of the wall 151 so that each and everyparticle is accelerated and travels upwardly along the concave side ofthe adjustable baffle 164. The flight span of heavier tobacco particlesis longer; therefore, such particles travel along the entire orsubstantially along the entire concave side of the baffle 164 andaccumulate in the receptacle 166 to be evacuated by the feed screw 167.The flight span of lighter tobacco particles (mainly shreds) is shorterso that such particles travel about the guide 168 and descend into thefunnel 171. The bristles 128 of the accelerating device 129 touch theadjacent protruberance of the wall 169 so that each and every lightertobacco particle is propelled with the same force to travel downwardlyand to come to rest on the upper stretch of the continuously movingstream transporting conveyor 104. The lighter particles form the growingtobacco stream 102 which is attracted to the upper side of the upperstretch of the transporting conveyor 104 by air admitted through theopening 172 at the rate determined by the setting of regulating valve173 and flowing downwardly into the suction chamber 106. The suctionchamber 106 may be connected with the intake of the blower 159 or to adiscrete suction generating device (not shown).

The manner in which the tobacco stream 102 is thereupon converted into afiller during travel below the trimming device 107 and is wrapped intothe web 109 of FIG. 3a to form a continuous wrapped filler rod orcigarette rod 118 is the same as described in connection with FIGS. 1aand 1b. The rod 118 is subdivided during travel through the cutoff 119of FIG. 3b to yield a single file of plain cigarettes which areaccelerated by the cam 121 and are propelled into successive flutes ofthe transfer conveyor 122. FIG. 3a shows that the width of the duct 146equals or approximates the length of the tobacco stream growing zone A.The length of this zone also equals the axial length of the drum 141,refuser 142, picker roller 144 and accelerating device 129.

It is clear that the accelerating device 129 of FIG. 4a can be replacedwith two discrete accelerating devices one of which forms part of theseparator to segregate lighter tobacco particles from heavier tobaccoparticles and cooperates with the wall 151, and the other of whichserves to accelerate the lighter tobacco particles which enter thefunnel 171 so that such particles are accelerated sufficiently to formon the transporting conveyor 104 a relatively dense tobacco stream 102,namely, a tobacco stream whose density preferably greatly exceeds halfthe density of the filler in the wrapped rod 118.

The mixture in the source 150 of FIG. 14a normally contains randomlydistributed shreds of tobacco leaves and comminuted tobacco ribs and/orstem. Since the ribs cannot be severed with the same degree of accuracyas tobacco leaf laminae, the mixture of ribs and shreds normallycontains smaller and larger fragments of ribs. The larger fragments ofribs should be prevented from entering the wrapping mechanism becausethey are likely to puncture the web 109 and/or to prevent the formationof a satisfactory seam. The segregation of larger fragments of ribstakes place in the separator chamber 162 of FIG. 4a. As mentioned above,the utilization of accelerating device 129 as a component part of themeans for segregating heavier tobacco particles from lighter tobaccoparticles constitutes an advantageous but optional feature of thedistributor 101 because the latter may comprise a classifying means orseparator which need not include the accelerating device 129. Forexample, comminuted tobacco which rises in the duct 146 of FIG. 4a canbe classified by resorting to one or more winnowers, and theaccelerating device 129 (or an analogous accelerating device) thenperforms the sole function of propelling the lighter tobacco particlesinto the channel 103 to form the stream 102.

FIG. 5 illustrates a portion of a distributor 201 which constitutes afirst modification of the distributor 101 of FIGS. 4a and 4b. All suchparts of the distributor 201 of FIG. 5 which are identical with orclearly analogous to the corresponding parts of the distributor 101 aredenoted by similar reference characters plus 100. The distributor 201 isdesigned for use in cigarette rod making machines which receive onlylighter tobacco particles, i.e., wherein the segregation of heaviertobacco particles takes place before the lighter particles are caused toenter the pneumatic conveyor duct 246. Therefore, the separator chamber162 of FIG. 4a has been omitted and the upper portion 246a of the duct246 is curved so as to direct the lighter tobacco particles into thefunnel 252. This funnel is defined in part by the bristles 228 of theaccelerating device 229 and in part by the wall 251 of the distributor201. The funnel 252 is located directly above the channel 203 for thetobacco stream 202 which grows on and travels with the upper stretch ofthe foraminous transporting conveyor 204. The suction chamber 206attracts the particles of the stream 202 to the transporting conveyor204 with a force which is determined by the setting of the regulatingvalve 273 in the opening 272. The inner side of the upper duct portion246a is flanked by a wall 253 provided with one or more openings orports 254 for admission of air into a suction chamber 256 connected tothe suction generating device (not shown in FIG. 5) by a pipe 257. Thewall 253 is of substantially semicylindrical shape. It will be notedthat the bristles 228 propel into the channel 203 each and everyparticle of tobacco which rises in the duct 246.

FIG. 6 illustrates a distributor 301 which constitutes a secondmodification of the distributor 101 shown in FIGS. 3a, 4a and 4b. Allsuch parts of the distributor 301 shown in FIG. 6 which are identicalwith or clearly analogous to the corresponding parts of the distributor101 are denoted by similar reference characters plus 200. The currentsof air flowing upwardly in the duct 346 of FIG. 6 introduce tobaccoshreds into a funnel 352 which is defined in part by protuberance of thewall 351 and in part by the bristles 328 of the accelerating device 329.The carrier medium which transports tobacco shreds in the duct 346upwardly is withdrawn by way of ports 354 provided in a second wall 353of the duct so that such air enters a suction chamber 356 which isconnected with the intake of the blower (not shown) by a suction pipe357.

The suction chamber 306 is provided in the uppermost part of thedistributor 301 above the lower stretch of the transporting conveyor 304which accumulates at its underside a growing tobacco stream 302. Thetobacco channel 303 is provided with an opening 372 for a regulatingvalve 373 which controls the rate of air flow through the tobacco stream302, through the foraminous transporting conveyor 304 and into thesuction chamber 306. The bristles 328 of the accelerating device 329propel the tobacco shreds which enter the funnel 352 so that theaccelerated shreds come to rest at the underside of the lower stretch ofthe transporting conveyor 304 and are attracted thereto by suction inthe chamber 306. The manner in which the tobacco stream 302 is thereuponconverted into a rod-like filler and into a wrapped filler rod is thesame as described in connection with FIGS. 1a and 1b. It will be notedthat the funnel 352 of FIG. 6 receives only tobacco shreds, i.e., thesegregation of tobacco shreds from ribs and/or stem takes place beforethe shreds enter the duct 346.

In the distributor 301, the accelerating device 329 is again located ata level between the feeding unit (not shown) and the transportingconveyor 304 but below the transporting conveyor, i.e., the bristlesmust propel the shreds upwardly with a force to insure that the densityof the stream 302 preferably exceeds half the density of the filler inthe wrapped rod.

FIG. 7 illustrates a distributor 401 which comprises a source of tobaccohere shown as a hopper or magazine 435 containing a supply of shreddedtobacco. Such tobacco is supplied by a conveyor belt 445 from a tobaccoshredding machine, not shown, and the belt 445 is preceded by aseparator which segregates the shreds from ribs and/or stem. Theconveyor 441 of the feeding unit is a drum having a carding 450 whichwithdraws shredded tobacco from the magazine 435 and cooperates with acarded refuser drum 442 of the feeding unit. The drums 441, 442 rotatein opposite directions and the drum 442 returns the surplus of shreddedtobacco into the magazine 435. The layer or carpet of tobacco shredswhich is held by the carding 450 is transported below a mechanicalretainer comb 443 and advances into the range of a rapidly rotatingpicker roller 444 which expels tobacco shreds from the carding 450 andpropels them into a funnel 434 defined by a suitable inclined baffle orwall 433 and the bristles 428 of an accelerating device 429.

The conveyor belt 445 is driven intermittently or continuously at avarying speed, and its drive means is controlled by a photoelectricdetector 440 which is mounted in or on the magazine 435 and producessignals in response to accumulation of a predetermined maximum supply ofshredded tobacco. When the detector 440 produces a signal, the speed ofthe conveyor belt 445 is either reduced or the conveyor belt 445 istemporarily arrested so as to insure that the level of tobacco shreds inthe magazine 435 cannot rise above the detector. The operating means forthe rapidly rotating accelerating device 429 comprises a discreteelectric motor 432 and a belt or chain transmission 431. The peripheralspeed of the accelerating device 429 invariably exceeds the peripheralspeed of the carded drum 441. The tips of bristles 428 touch the innerside of the baffle 433 so as to insure that each and every tobacco shredwhich enters the funnel 434 is accelerated at the same rate to bepropelled downwardly along a second baffle 436 and to enter the channel403. The walls 426 and 427 of the channel 403 are configurated in thesame way as described in connection with the walls 26, 27 shown in FIG.2. The growing tobacco stream 402 accumulates on the upper stretch of aforaminous transporting conveyor 404 which travels about a suctionchamber 406. The suction chamber 406 draws currents of air from theatmosphere above the open upper end of the channel 403, and suchcurrents pass through the tobacco stream 402 and the openings orinterstices of the transporting conveyor 404 to enter the suctionchamber 406 in order to prevent the conveyor 404 from slipping relativeto the shreds which form the stream 402.

The operation of the distributor 401 is as follows:

The conveyor belt 445 supplies tobacco shreds into the magazine 435whenever the level of the supply of tobacco in this magazine is belowthe detector 440. This insures that the magazine 435 contains .[.at.]..Iadd.a .Iaddend.constant supply of tobacco shreds which insures auniform rate of withdrawal of tobacco shreds by the carding.[.carding.]. 450 of the drum 441. The carding of the refuser 442removes the surplus of tobacco shreds from the carding 450 and theremaining (equalized) layer of tobacco shreds travels below themechanical retainer 443 to move into the range of the rapidly rotatingpicker roller 444. The picker roller 444 propels the shreds against theinner side of the baffle 433 along which the shreds descend by gravityto enter the funnel 434 and to thus move into the range of rapidlyorbiting bristles 428 of the accelerating device 429 which is driven bythe electric motor 432 at a speed exceeding the speed of the carding450. The bristles 428 accelerate the shreds and propel them directlyinto the channel 403 or against the inner side of the second baffle 436so that the shreds accumulating on the upper stretch of the transportingconveyor 404 form a relatively dense tobacco stream 402. As mentionedbefore, the density of this tobacco stream is perferably more than halfthe density of the filler in the wrapped rod which leaves the wrappingmechanism of the cigarette rod making machine embodying the distributor401. The energy of tobacco shreds which are propelled by the bristles428 greatly exceeds the energy of shreds which would descend by gravityfrom the funnel 434 directly into the channel 403. The suction chamber406 holds the shreds of the stream 402 against slippage relative to theupper stretch of the transporting conveyor 404 which advances the streamtoward the trimming device, not shown in FIG. 7. The acceleration ofshreds which are propelled downwardly by the bristles 428 is sufficientto insure that the shreds forming the tobacco stream 402 not onlydeposit on top of each other but that the shreds also penetrate into theinterstices between adjoining shreds which further contributes togreater density and uniformity of the stream 402. As explained inconnection with FIG. 2, the density of the stream 402 is preferablysufficient to insure that this stream expands only slightly if thesuction in the chamber 406 is terminated. In other words, when comparedto the densifying and accelerating action of the bristles 428, thedensifying action of air flowing into the chamber 406 is negligible.

An important advantage of the improved distributors is that they arecapable of building a continuous tobacco stream wherein the particles oftobacco are densely packed so that the density of the entire stream atthe upper side or at the underside (see FIG. 6) of the transportingconveyor is uniform all the way from the adjacent stretch of thisconveyor and to the exposed surface of the stream. The electric motor oranother prime mover which drives the accelerating device is preferablyadjustable so that it can drive the bristles at a selected speed whichis sufficient to build on the transporting conveyor a tobacco stream ofdesired density. Thus, the density of the tobacco stream is a functionof the spped at which the bristles orbit about the axis of theaccelerating device. Uniform density of the tobacco stream which isformed in the channel of the distributor is desirable because suchstream can be readily equalized or trimmed to form a filler rod whosedensity is uniform in each and every zone thereof.

The distributors of FIGS. 2 and 7 (particularly the distributor of FIG.7) exhibit the additional advantage that the magazine for the tobaccoshreds can be placed very close to the channel 3 or 403. This insuresthat the consistency of shreds is changed very little during transferonto the stream transporting conveyor. In addition, and as mentionedbefore, the carding 450 of the conveyor 441 shown in FIG. 7 is capableof withdrawing tobacco shreds at a uniform rate because the upper levelof the mass of tobacco shreds in the magazine 435 fluctuates very littleor not at all. The manner in which a detector 440 can control the motoror transmission for the conveyor belt 445 is well known in theart.[.,.]. and, therefore, the operative connection between the detector440 and the belt 445 has not been shown in FIG. 7. It is clear, however,that the magazine 435 of FIG. 7 can also receive a mixture containingshreds and tobacco ribs and/or stem if the nature of the final productis such that its filler can contain both types of tobacco. The sameholds true for the distributor 1, 101, 201 and/or 301.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is:.[.set forth in the appended claims.].
 1. In a machine for the making oftobacco filler rods, apparatus for building a tobacco stream comprisinga source of comminuted tobacco; a tobacco feeding unit arranged to drawtobacco from said source and including a first conveyor operable at aplurality of speeds to transport the withdrawn tobacco along a firstportion of a predetermined path; a tobacco stream transporting secondconveyor adjacent to means defining a relatively narrow second portionof said path; an accelerating device comprising a rotary conveyor andwall means defining with said rotary conveyor a funnel which receivestobacco supplied by said first conveyor, said accelerating device beingdisposed between said .Iadd.first and second .Iaddend.conveyors andoperative to mechanically accelerate comminuted tobacco for transferinto and densification in said narrow second portion of said pathwherein the accelerated tobacco forms a narrow growing stream which istransported by said second conveyor; and means for operating saidaccelerating device independently of at least one of said .Iadd.firstand second .Iaddend.conveyors.
 2. Apparatus as defined in claim 1,wherein said first conveyor is located at a level above saidaccelerating device and the tobacco descends by gravity into the rangeof said accelerating device.
 3. Apparatus as defined in claim 1, whereinsaid first conveyor is located at a level below said second conveyor. 4.Apparatus as defined in claim 1, wherein said second conveyor is locatedat a level above said accelerating device.
 5. Apparatus as defined inclaim 1, wherein said accelerating device is located at a level abovesaid second conveyor.
 6. Apparatus as defined in claim 1, furthercomprising means for classifying the particles of comminuted tobacco inadvance of said accelerating device.
 7. Apparatus as defined in claim 6,wherein said classifying means is located at a level above saidaccelerating device.
 8. Apparatus as defined in claim 1, wherein saidfirst conveyor is arranged to draw tobacco from said source and saidfeeding unit further comprises means for removing tobacco from saidfirst conveyor, said accelerating device being disposed at a level abovesaid second conveyor and below said removing means and said removingmeans being arranged to supply tobacco to said accelerating device bygravity flow.
 9. Apparatus as defined in claim 8, wherein said firstconveyor is a carded conveyor and said removing means comprises a pickerroller.
 10. Apparatus as defined in claim 9, wherein said feeding unitfurther comprises refuser means for equalizing the comminuted tobaccowhich is being drawn from said source by said carded conveyor. 11.Apparatus as defined in claim 1, further comprising an elongated tobaccochannel provided with an elongated suction chamber, said second conveyorconsisting of foraminous material and having an elongated stretch oneside of which is adjacent to said chamber and the other side of whichreceives tobacco from said accelerating device.
 12. Apparatus as definedin claim 1, wherein said second portion of said path is substantiallynormal to said first portion of said path, said first conveyor beingarranged to supply a sliver of comminuted tobacco and said acceleratingdevice comprising a rotary conveyor having an axial length at leastapproximating the width of the sliver on said first conveyor. 13.Apparatus as defined in claim 1, further comprising prime mover meansfor driving said first conveyor in synchronism with said secondconveyor, said means for operating said accelerating device comprising adiscrete motor.
 14. Apparatus as defined in claim 13, wherein said firstand second conveyors are endless belts.
 15. Apparatus as defined inclaim 1, wherein the filler rod produced by said machine has apredetermined density and said means for operating said acceleratingdevice comprises means for driving said rotary conveyor at a peripheralspeed which is high enough to impart to comminuted tobacco a kineticenergy sufficient to build on said second conveyor a tobacco streamwhose density exceeds one-half of said predetermined density. .Iadd. 16.In a machine for the making of tobacco filler rods, apparatus forbuilding a tobacco stream comprising a source of intermixed lighter andheavier tobacco particles, particularly intermixed tobacco shreds andribs; a tobacco feeding unit arranged to draw tobacco particles fromsaid source and including a first conveyor operable at a plurality ofspeeds to transport the withdrawn tobacco particles along a firstportion of a predetermined path; channel means defining a relativelynarrow second portion of said path; a second conveyor adjacent to saidchannel means and arranged to transport tobacco particles along saidsecond portion of said path; means for transferring tobacco particlesfrom said first conveyor and for transferring lighter particles ontosaid second conveyor, including an accelerating device comprising arotary third conveyor and wall means defining with said third conveyor afunnel which receives tobacco particles supplied by said first conveyor,said accelerating device being disposed intermediate said first andsecond conveyors and being operative to mechanically accelerate saidlighter and heavier particles whereby the flight spans of said heavierparticles are different from the flight spans of said lighter particleswith attendant segregation of said lighter particles from said heavierparticles, said lighter particles being transferred into and densifiedin said channel means wherein said lighter particles form a narrowgrowing stream which is transported by said second conveyor; means foroperating said third conveyor independently of at least one of saidfirst and second conveyors; and means for intercepting said segregatedheavier particles. .Iaddend..Iadd.
 17. Apparatus defined in claim 16,wherein said transferring means further comprises means for removinglighter and heavier tobacco particles from said first conveyor..Iaddend..Iadd.
 18. Apparatus as defined in claim 17, wherein saidlighter and heavier tobacco particles form on said first conveyor arelatively wide sliver and said first conveyor is a carded conveyor..Iaddend..Iadd.
 19. Apparatus as defined in claim 18, wherein saidremoving means comprises a picker roller. .Iaddend..Iadd.
 20. Apparatusas defined in claim 16, wherein said third conveyor comprises asubstantially cylindrical brush having an annulus of bristles..Iaddend..Iadd.
 21. Apparatus as defined in claim 16, wherein saidoperating means includes means for rotating said third conveyor at aperipheral speed exceeding each of said plurality of speeds..Iaddend..Iadd.
 22. Apparatus as defined in claim 16, further comprisinga separator chamber for said funnel and said intercepting means..Iaddend.